All cells have a time when they will stop dividing. this process is programmed cell death called

This is called regulating signals there are two kinds of regulating signal  first Regulating signals that tell cells to divide can turn off or regulating signals that tell cells to stop dividing can turn on

2nd Signals tell cells to die programmed cell death-internal series of events). 

well first you need the sample of the temperature and gas level. i couldnt write a hypothesis unless i had some data. i think temperature changes will effect volumes of gas because gas changed into a solid or liquid at specific temperatures.